Routine response -
There are products purchased by the customer without any second thought. There is very less amount of time customer takes to make the buying decision. There are certain products like bread, butter etc. over which consumer has a fixed thought. Example, you go to the store to buy a bread, chances are either you will select from the variety you are familiar with or will buy the reasonable priced one.
Limited decision making -
People need some time to gather information over the products which are bought occasionally. Customer have to do research before purchasing because they need time to make the decision.
Extensive decision making -
Here, high involvement is needed for the research as the customer is unfamiliar with the products before. Example, you want to buy a new house and this requires huge investment and you've never experienced this before. The products will be too expensive and that includes economic risk also as you must have taken some loans to finance either the house or the house products.
It requires no planning , evaluation or thought. Example, you go to a grocery store to buy bread but suddenly you saw a new collection of chocolates, you just want that chocolate and didnt thought of buying it before and you made that purchase.